If you have company delivery vehicles at your small or medium sized business you should have a preventative maintenance schedule and procedures for employees who are drivers of these vehicles. When discussing preventative maintenance over the years with business owners the first thing which comes to mind is Oil change and usually the business owner who is on the hook for the loans on these vehicles is more than aware of that fact. Yes, you should change the oil. Obviously you should. How about every 3,000 5000 miles. After all, that kind of driving is hard on a vehicle, not to mention:

Starting and stopping

Speed bumps

Stop and go traffic

Water movement

Workers driving truck

Driving in dusty conditions

Towing trailers

Excessive idling

While you are waiting to fill up with gas, you should have employees Armor-All the tires, hand out business cards, wipe off rims, clean inside windows and:

Check engine oil level, add as required

Check windshield washer solvent and add if required

Once per month you should do an extensive pre-flight check of your truck. On the first Monday of each month:

Check tire pressure and look for unusual wear or damage

Inspect battery and clean and tighten terminals as required

Check fluid levels of coolant reservoir, power steering and transmission and add as needed

Check all lights and all other electrical items for correct operation to prevent fix-it type tickets humiliating your driver and detracting from your company since the logos are on the side of the vehicle for advertising. Develop a quick form with these items listed and be diligent about checking them on a certain day each month, you will be glad you did, it adds money to the wholesale value of the vehicle and could save your small business thousands of dollars in unnecessary repairs, towing and lost business due to down time.